Printed substrate exit devices for imaging and printing systems, such as electrophotographic imaging and printing systems, are known in the art. Exit devices are designed to provide efficient, controlled, exit of the printed substrate from a printing site of the imaging system. The printing site is typically an impression region between the substrate and a member carrying a toner or ink image. In many existing systems, an impression roller provides positive contact between the image carrying member and the substrate.
To provide efficient, slip-free, removal of the printed substrate from the impression region, a portion of the exit device must be urged against the printed side of the substrate. However, to avoid deformation of the yet incompletely fixed image upon exit from the impression region, the exit device preferably includes a smooth surface and the area of contact between the exit device and the printed surface is preferably minimized. Thus, existing exit devices include rigid, smooth elements, for example a plurality of narrow rollers, contacting only a portion of the width of the printed surface. This structure results in slight image deformation, such as loss of glossiness, in the form of streaks corresponding to the regions of contact between the rollers and the printed surface.
PCT Publication WO 93/04409 describes a duplex imaging system having such an exit device. The exit device used in WO 93/04409 includes a pair of thin, rigid, rollers which urge the printed substrate against the impression roller, downstream of the impression region. The exit rollers are rotatably mounted on an axle which is also utilized as part of a substrate deflection arrangement of the duplex imaging system.
Substrate feeder rollers for feeding printing substrate into the impression region are known in the art. Since there is no image on the substrate being fed, there are no particular restrictions on the contact area between the feeding roller and the substrate. Therefore, the feeding roller is typically in contact substantially with the entire width of the substrate. U.S. Pat. No. 4,287,649 describes a substrate feeder-roller which contacts the entire width of the printing substrate. The roller of U.S. Pat. No. 4,287,649 is formed of a thick, spongy, interior coated with a thin, smooth or textured, outer shell.